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Biomedical subjects

G Herrmann

Publications and source records attributed to G Herrmann.

At least 19 recordsLinked to original sources
PubMed1992

[An aortopulmonary shunt after a knife wound].

An extensive hemopneumothorax developed in a 23-year-old man after having been knifed in the region of the left nipple. After general surgical care a Bülau suction drain was inserted. Cardiological examination became necessary a week later when a chest X-ray film demonstrated an enlarged cardiac silhouette. Echocardiography revealed pericardial effusion (about 600 ml) which was removed by pericardial aspiration. Cross-sectional and colour Doppler echocardiography showed a shunt between the aorta and right ventricular outflow tract at the origin of the pulmonary artery. At surgery a fistula between the root of the aorta and the pulmonary artery was identified (the posterior sinus near the anulus was nearly completely detached). The fistula was closed and the pulmonary valve reconstructed. The early and late postoperative course was unremarkable.

Adult↗
PubMed1992

[Proliferation kinetic studies in the syngeneic liver transplantation mode in the rat. Effect of re-arterialization on the transplant].

Successful orthotopic liver transplantation (OLT) can be achieved in the rat. We used bromo-2-deoxyuridine (BrdU) as a proliferation marker to document morphological differences between OLT with and without rearterialization. Animals with portal anastomosis alone had a significantly increased proliferation rate of hepatocytes, Kupffer cells, and bile duct epithelial cells, as indicated by strong staining with BrdU, 8 days post-transplant compared to animals with rearterialization. Regeneration of ischemically damaged liver parenchymal cells may account for this observation. Thus, OLT with rearterialization appears to be the more physiological transplant model.

Anastomosis, Surgical↗
PubMed1992

Structure-activity relationship between (E)-5-(2-bromovinyl)- and 5-vinyl-1-beta-D-arabinofuranosyluracil (BV-araU, V-araU) in inhibition of Epstein-Barr virus replication.

The structure-activity relationship between (E)-5-(2-bromovinyl)- and 5-vinyl-1-beta-D-arabinofuranosyluracil (BV-araU and V-araU) in inhibition of Epstein-Barr virus (EBV) was evaluated. Both V-araU and BV-araU effectively inhibited EBV replication in virus-producer P3HR-1(LS) cells, as determined by DNA-DNA hybridization. The 50% effective doses (ED50) for viral DNA replication were 0.005 and 0.3 microM for V-araU and BV-araU, respectively. The in vitro therapeutic index was 4000 for V-araU and 1300 for BV-araU. Synthesis of EBV-induced polypeptides with molecular weights of 145,000 (145, 140, 130, and 110 kDa) was significantly inhibited by both drugs. Only V-araU inhibited the synthesis of 85-, 55-, and 32-kDa polypeptides by approx. 50%. Kinetic analysis of inhibition and reversibility of EBV DNA replication after removal of the drugs indicated that BV-araU has a more prolonged inhibitory effect than V-araU. These results indicate that the substitution of H by Br in the 5-vinyl group results in marked reduction in anti-EBV activity while prolonging the drug effect and diminishing cytotoxicity.

Antiviral Agents↗
PubMed1992

Immunocytochemical characterization of cytomegalovirus (CMV) infected giant cells in perinatal acquired human immunodeficiency virus (HIV) infection.

In a pediatric case of necrotizing CMV myelitis after perinatal HIV infection characteristic cytomegalic cells, which could not be attached to a particular cell line by cell morphology, were studied after immunostaining with monoclonal and polyclonal antibodies raised against GFAP, S100 protein, NSE, synaptophysin, factor VIII, vimentin, macrophages, leukocytes, CMV, HSV I + II, toxoplasma, and HIV 1 gp41. Astrocytes, oligodendrocytes, neurons, ependymal and endothelial cells, macrophages, and Schwann cells stained positively with CMV antiserum. With regard to their immunological features the majority of cytomegalic cells ("owl eye cells") was identified as astrocytes, and in decreasing frequency, the remainder was characterized as macrophages, mesenchymal, and endothelial cells. It is concluded that CMV giant cells represent one phase of virus induced cell transformation, not only one single, but numerous cell types are exposed to after CMV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Rapid development of giant aneurysm at the base of the brain in an 8-year-old boy with perinatal HIV infection.

An 8-year-old boy with perinatal HIV infection developed a large fusiform aneurysm in the circle of Willis two years prior to death which was confirmed by radiological studies. The postmortem examinations revealed a predominantly intimal, proliferative lesion, and partial destruction of the internal elastic lamina in the involved arteries. Within the intima hyperplasia of fibroblasts and smooth muscle cells was observed. No inflammatory alterations, no granulomas and no multinucleated giant cells could be noted in the vascular walls and in the cerebral parenchyma. A small ischemic infarct was present in the left thalamus. Cerebellum, brainstem and medulla showed multiple areas of progressive multifocal leukoencephalopathy (PML). Immunohistochemistry with anti-gp41, a monoclonal antibody against HIV envelope did not exhibit any positive results. These findings implicate that the vascular lesion might be attributed to primary infection of the brain by HIV which led to a defect of elastic lamina and consecutive intimal hyperplasia. A second hypothesis could be based on the effect of extremely high dose AZT therapy avoiding inflammatory reaction after HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Stimulation of cell division and fibroblast focus formation by antisense repression of retinoblastoma protein synthesis.

Circumstantial evidence supports a role for the retinoblastoma susceptibility gene, Rb-1, in the maintenance of normal cell growth, in that loss of its function results in abnormal growth and malignancy. Here we report that a high rate of mitosis and efficient dense focus formation in human embryonic lung fibroblasts (HEL cells) is induced by antisense oligonucleotide-directed inhibition of synthesis of p105-Rb, the product of the Rb-1 gene. mRNA specific for p105-Rb is truncated at the site of base pairing with the antisense oligonucleotide, and no synthesis of p105-Rb is observed. The rate of mitosis is considerably increased and the frequency of dense focus formation is extremely high in treated cells. However, although phosphothioate oligodeoxyribonucleotides taken up by the cells remain stable for at least 4 weeks, the recipient cells do not become immortal; nor are they able to induce tumor formation in nude mice. Thus, loss of Rb-1 function is not sufficient per se to allow malignant transformation.

Base Sequence↗
PubMed1992

[Additive effects of milrinone and dobutamine in severe heart failure].

The hemodynamic effects of dobutamine, milrinone, and a combination of both drugs were compared intra-individually in 14 patients with severe heart failure (NYHA III: n = 9; NYHA IV: n = 5). Dobutamine (maximum dose: 9 micrograms/kg/min) and milrinone (0.5 micrograms/kg/min) each induced a comparable increase in stroke volume index (21 to 29 resp. 21 to 30 ml/m2; mean values; p less than 0.001) and reduction in pulmonary capillary wedge pressure (29 to 22 resp. 28 to 21 mm Hg; p less than 0.001), as well as in systemic (1846 to 1218 resp. 1858 to 1276 dyn s/cm5; p less than 0.001) and pulmonary vascular (301 to 195 resp. 293 to 216 dyn s/cm5; p less than 0.001) resistances. The heart rate rose significantly after dobutamine (92 to 107 min-1; p less than 0.05), but did not change after milrinone (94 to 95 min-1; ns). Neither drug had a significant effect on systemic arterial pressures. The combination of milrinone and dobutamine induced a further significant rise in stroke volume index (37 ml/m2; p less than 0.01) when compared to either drug alone. The combination also caused an additional fall in pulmonary capillary wedge pressure (14 mm Hg; p less than 0.01), as well as in systemic (799 dyn s/cm5; p less than 0.001) and pulmonary (133 dyn s/cm5; p less than 0.001) vascular resistances. When compared to dobutamine alone, the combined therapy did not significantly change the heart rate and systemic arterial pressures. The combined administration of a beta-adrenergic agonist and a phosphodiesterase inhibitor induces beneficial hemodynamic effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Inferior vena cava compression syndrome in cystic kidney. Duplex ultrasonic diagnosis].

Four months after renal transplantation for polycystic renal degeneration a 38-year-old man developed breathing-related pain in the left upper lung and a sinus tachycardia (130/min). Lung perfusion scintigraphy demonstrated pulmonary emboli from an acute venous thrombosis of the left lower leg. Polycythaemia and impairment of clot-inhibiting factors were excluded. Ultrasound examination of the abdomen revealed stenosis of the inferior vena cava (IVC) distal to the hepatic veins, dorsal to the liver and ventral of a huge right polycystic kidney which had been left in situ at the time of the renal transplantation. Duplex sonography demonstrated a band-like flow profile in the region of the stenosis. Blood flow was clearly increased (0.62 m/s) and not affected by either heart rate or breathing movements. The findings were confirmed by angiography. The right kidney, weighing 5 kg, was removed at surgery. The IVC stenosis was postoperatively found to be relieved and duplex sonography gave normal findings.

Adult↗
PubMed1991

Functional significance of sequences following the TATA box of an immunoglobulin promoter studied by random mutagenesis.

We have investigated the importance of sequences downstream to the TATA box of an immunoglobulin promoter by transfection and in vitro transcription assays. A sequence from -11 to +10 with respect to the transcriptional start site was synthesised by a procedure allowing for random misincorporation of nucleotides. The pool of mutant oligonucleotides was cloned into the respective position of a vector carrying a fusion of a synthetic immunoglobulin heavy chain promoter with the human growth hormone gene. From 200 clones sequenced, 115 were mutants with at least one nucleotide exchange in every position. Whereas most mutations are of minor functional importance, changes at or near the transcriptional start site reduce the promoter activity considerably.

Base Sequence↗
PubMed1991

Evidence for multiple xenogenous origins of plastids: comparison of psbA-genes with a xanthophyte sequence.

When only plastidic features are considered, it is difficult to distinguish between monophyletic and polyphyletic xenogenous origins of plastids. We suggest that a direct comparison of nuclear and plastidic sequence-similarity pattern will help to solve this problem. The D1 amino acid sequence of six major groups of photosynthetic eukaryotes and of the two groups of photosynthetic prokaryotes are now available, including the psbA-gene product from Bumilleriopsis filiformis, which is the first molecular sequence reported for a xanthophycean alga. Evidence is provided for an independent and polyphyletic origin of plastids from five out of the six major taxa of photosynthetic eukaryotes. This conclusion is reached by comparing a plastid-based pattern of D1 similarity with a nucleus-based similarity pattern published recently. Furthermore, the availability of D1 sequences from five eukaryotic algae led to a re-evaluation of the taxonomic position of Prochlorothrix.

Amino Acid Sequence↗
PubMed1991

The effects of pretreatment with nitroglycerin on ischemic left ventricular dysfunction during coronary angioplasty.

To evaluate the degree to which nitroglycerin reduces myocardial ischemia and dysfunction induced by transient coronary occlusion, 19 patients were studied during coronary angioplasty of the left anterior descending coronary artery. After a control occlusion of 60 seconds, 0.2 mg nitroglycerin was administered intravenously and the occlusion was repeated for 60 seconds. Before and during the occlusion period, pulmonary capillary wedge pressure was measured, the intracoronary ECG was recorded, and ventricular volumes, ejection fraction, and regional systolic shortening were obtained by digital subtraction angiography. Nitroglycerin caused a significant fall in pulmonary capillary wedge pressure before (10 vs. 7 mmHg) and at 60 seconds occlusion (18 vs. 14 mmHg), but did not significantly delay the rise in wedge pressure (37 vs. 44 seconds). End-systolic left ventricular volume at 60 seconds of occlusion was reduced by nitroglycerin (77 vs. 68 ml), whereas regional shortening of the ischemic segments remained unchanged (22 vs. 23%). Nitroglycerin did not delay the onset of ischemic ST-segment elevation (14 vs. 14 seconds) and had no effect on the changes of ST elevation in the intracoronary ECG (1.9 vs. 1.9 mV). These findings suggest that intravenous nitroglycerin reduces filling pressure and slightly improves left ventricular global function during acute coronary occlusion. Nitroglycerin, however, has little effect on ischemia-induced regional dysfunction and on ST-segment elevation in the intracoronary ECG.

Adult↗
PubMed1991

[Dose and time dependence of hemodynamic tolerance development during intravenous nitrate therapy in acute myocardial infarct].

Intravenous nitroglycerin therapy during acute myocardial infarction has beneficial effects on infarct size, infarct complications, and mortality. Numerous dosage formulas for the continuous administration of nitrates are currently used, although several studies have demonstrated the rapid development of tolerance during long-term treatment in patients with ischemic heart disease. The dose and dosage of a continuous nitrate application in the clinical setting of acute myocardial infarction has thus yet to be resolved. This study investigated the hemodynamic effects of a 60-h, low- (33 micrograms/min) vs high- (133 micrograms/min) dose intravenous nitroglycerin (NTG) infusion in 16 patients with uncomplicated acute myocardial infarction. In group I (33 micrograms/min NTG; n = 8) the initial nitrate effect on the pulmonary capillary pressure (PCP-control: 14 +/- 1.5; 4 h: 7 +/- 0.9; 60 h: 7 +/- 0.8; mean +/- SEM; all values in mm Hg) and mean pulmonary artery pressure (PAPM-control: 23 +/- 2.3; 4 h: 15 +/- 1.3; 60 h: 14 +/- 1.3) remained unchanged for 60 h. In group II (133 micrograms/min NTG; n = 8) an almost complete loss of the initial effect on PCP (control: 15 +/- 1.6; 4 h: 5 +/- 1.4; 60 h: 12 +/- 1.3) and PAPM (control: 25 +/- 2.0; 4 h: 14 +/- 1.8; 60 h: 20 +/- 1.3) was observed. In contrast to high-dose application the low-dose NTG-infusion induced comparable acute hemodynamic effects that were not attenuated by tolerance development.

Aged↗
PubMed1991

[Experiences with the application of monoclonal Indium-111 antimyosin scintigraphy in the diagnosis of rejection episodes following orthotopic heart transplantation].

Indium-111-labeled Fab fragment imaging using a murine antimyosin monoclonal antibody (Myoscint, Centocor, Leiden) was evaluated for efficacy in detecting cardiac allograft rejection. Diagnosis of rejection was made by endomyocardial biopsy with four to five samples taken for each procedure. Eighty-one studies were performed in 25 patients (21 men, four women, mean age 50 +/- 9 years) from 2 weeks to 45 months after cardiac transplantation. 0.5 mg of the monoclonal antibody labeled with 60 MBq Indium-111 (Antimyosin-Fab-DTPA) was administered i.v. Planar scintigraphic images were obtained in LAO 45 and anterior projections as well as "half-body-scintigrams" 48 h after injection. Using the regions-of-interest-(ROI)technique the relative uptake over the lung and the heart was determined and an index of In-111 uptake was calculated. A heart-to-lung ratio of 1.5 or higher was considered indicative for moderate to severe rejection. Specificity was 86% (nine false-positive In-111 studies in 68 negative biopsy studies), sensitivity was 85% (two false-negative In-111 studies in 13 pathological biopsy studies). It is concluded that the In-111 method has a high sensitivity and specificity in detecting heart transplant rejection and may be useful in the monitoring of patients in the chronic phase after heart transplantation. The 48-h delay in establishing the diagnosis limits the applicability in acute severe rejection.

Adult↗
PubMed1990

Comparison of three different principles in the assessment of coronary flow reserve from digital angiograms.

In 70 patients without coronary disease we have compared three different principles to assess coronary flow reserve during diagnostic heart catheterization. Digital angiograms with ECG-triggered bolus injections of 4 to 8 ml of contrast medium at rest and after stimulation by dipyridamole (0,5 mg/kg i.v.) or papaverine (12,5 mg i.c.) were acquired in a 512 x 512 matrix at 8 bit resolution (ADAC 4100) and stored on a digital disk at 25 frames/sec. or 2 frames/cardiac cycle (PPR-mode). Angiograms were processed by cyclic R-wave-gated mask mode subtraction and coronary flow in the LAD area was assessed by three different approaches: 1. A traditional densitometric principle. 2. The 'CMAP' principle. 3. A modification of the Stewart-Hamilton principle comparing the total amount of contrast medium that enters the coronary circulation to the area of the contrast dilution curve in a fixed portion of the LAD. Flow was measured simultaneously during angiography using the thermodilution technique for coronary sinus/great cardiac vein flow. Drug stimulation resulted in an increased coronary blood flow up to five times of resting flow. Regression analysis revealed the following results for the assessment of the coronary flow reserved by digital angiography (y) when compared to thermodilution (x): [table: see text] Method 2 could be improved by replacing the density factor by morphometrically measured proximal LAD volume (y = 0.77x + 0.55; r = 0.78; SEE = +/- 0.43). In conclusion, our data suggest that the Stewart-Hamilton principle may be advantageous over time parameter-dependent approaches in the assessment of coronary flow reserve by digital angiography.

Adult↗
PubMed1990

Protective effects of pretreatment with intracoronary nifedipine on myocardial ischemia and dysfunction.

To assess whether pretreatment with intracoronary nifedipine protects the myocardium against acute ischemia induced by coronary occlusion, 18 patients were studied during coronary angioplasty of the left anterior coronary artery. After a control occlusion of 60 seconds, 0.1 mg nifedipine was injected and occlusion was repeated for 60 seconds. Before and during the occlusion period, pulmonary capillary pressure was measured and the intracoronary epicardial ECG was recorded. After intracoronary administration of nifedipine, the onset of the rise in diastolic filling pressure was delayed from 23 to 38 seconds (p less than 0.01) and the changes at 60 seconds of occlusion were reduced from 14 to 11 mmHg (p less than 0.05). Nifedipine delayed the appearance of ischemic ST-segment elevation in the intracoronary ECG from 11 to 21 seconds (p less than 0.01) and diminished the changes at 60 seconds of occlusion from 1.8 to 1.2 mV (p less than 0.05). These findings suggest that pretreatment with intracoronary nifedipine protects the myocardium against some of the mechanical and electrocardiographic consequences of regional ischemia during acute coronary occlusion.

Adult↗
PubMed1990

Acute hypercalcemic crisis after an open heart operation.

Acute hyperparathyroidism developed in a previously normocalcemic 64-year-old woman during the first week after a coronary operation. Prolonged QT interval in the electrocardiogram and hypercalcemia were documented on the fourth postoperative day. Neck exploration on the fifth postoperative day revealed a lower right parathyroid adenoma. Parathyroidectomy resulted in rapid and dramatic improvement of the clinical picture and normalization of laboratory values.

Acute Disease↗